U.S. Pat. No. 6,128,893 (corresponding to Taiwanese patent application No. TW86116801) and U.S. Pat. No. 5,038,556 all disclose a header of a cable guiding chain. For example, using U.S. Pat. No. 6,128,893 as an example, the header comprises a base plate and two side plates spaced apart from each other and provided to two sides of the base plate, the base plate and the two side plates cooperate to form a receiving space having an opening opened upwardly, a cable may be placed into the receiving space via the opening of the header and pass through the header so as to be connected to a plug connector. However, a problem easily resulted from such a header lies in that, because the header has the opening, a part of the cable is exposed out of the header via the opening, when the cable guiding chain is pulled to move, the cable guiding chain may scrape the part of the cable exposed out of the header via the opening, thereby resulting in the cable to be worn, and even resulting in the cable to leak current, short-circuit or affect a signal transmission and so on, finally affecting performance stability of the cable.